hwmon (occ): Add sysfs attributes for additional OCC data

The OCC provides a variety of additional information about the state of
the host processor, such as throttling, error conditions, and the number
of OCCs detected in the system. This information is essential to service
processor applications such as fan control and host management.
Therefore, export this data in the form of sysfs attributes attached to
the platform device (to which the hwmon device is also attached).

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 188 insertions, 0 deletions

diff --git a/drivers/hwmon/occ/sysfs.c b/drivers/hwmon/occ/sysfs.c
new file mode 100644
index 000000000000..743b26ec8e54
--- /dev/null
+++ b/drivers/hwmon/occ/sysfs.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OCC hwmon driver sysfs interface
+ *
+ * Copyright (C) IBM Corporation 2018
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+
+#include "common.h"
+
+/* OCC status register */
+#define OCC_STAT_MASTER			BIT(7)
+#define OCC_STAT_ACTIVE			BIT(0)
+
+/* OCC extended status register */
+#define OCC_EXT_STAT_DVFS_OT		BIT(7)
+#define OCC_EXT_STAT_DVFS_POWER		BIT(6)
+#define OCC_EXT_STAT_MEM_THROTTLE	BIT(5)
+#define OCC_EXT_STAT_QUICK_DROP		BIT(4)
+
+static ssize_t occ_sysfs_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	int rc;
+	int val = 0;
+	struct occ *occ = dev_get_drvdata(dev);
+	struct occ_poll_response_header *header;
+	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
+
+	rc = occ_update_response(occ);
+	if (rc)
+		return rc;
+
+	header = (struct occ_poll_response_header *)occ->resp.data;
+
+	switch (sattr->index) {
+	case 0:
+		val = !!(header->status & OCC_STAT_MASTER);
+		break;
+	case 1:
+		val = !!(header->status & OCC_STAT_ACTIVE);
+		break;
+	case 2:
+		val = !!(header->status & OCC_EXT_STAT_DVFS_OT);
+		break;
+	case 3:
+		val = !!(header->status & OCC_EXT_STAT_DVFS_POWER);
+		break;
+	case 4:
+		val = !!(header->status & OCC_EXT_STAT_MEM_THROTTLE);
+		break;
+	case 5:
+		val = !!(header->status & OCC_EXT_STAT_QUICK_DROP);
+		break;
+	case 6:
+		val = header->occ_state;
+		break;
+	case 7:
+		if (header->status & OCC_STAT_MASTER)
+			val = hweight8(header->occs_present);
+		else
+			val = 1;
+		break;
+	case 8:
+		val = occ->error;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", val);
+}
+
+static SENSOR_DEVICE_ATTR(occ_master, 0444, occ_sysfs_show, NULL, 0);
+static SENSOR_DEVICE_ATTR(occ_active, 0444, occ_sysfs_show, NULL, 1);
+static SENSOR_DEVICE_ATTR(occ_dvfs_overtemp, 0444, occ_sysfs_show, NULL, 2);
+static SENSOR_DEVICE_ATTR(occ_dvfs_power, 0444, occ_sysfs_show, NULL, 3);
+static SENSOR_DEVICE_ATTR(occ_mem_throttle, 0444, occ_sysfs_show, NULL, 4);
+static SENSOR_DEVICE_ATTR(occ_quick_pwr_drop, 0444, occ_sysfs_show, NULL, 5);
+static SENSOR_DEVICE_ATTR(occ_state, 0444, occ_sysfs_show, NULL, 6);
+static SENSOR_DEVICE_ATTR(occs_present, 0444, occ_sysfs_show, NULL, 7);
+static SENSOR_DEVICE_ATTR(occ_error, 0444, occ_sysfs_show, NULL, 8);
+
+static struct attribute *occ_attributes[] = {
+	&sensor_dev_attr_occ_master.dev_attr.attr,
+	&sensor_dev_attr_occ_active.dev_attr.attr,
+	&sensor_dev_attr_occ_dvfs_overtemp.dev_attr.attr,
+	&sensor_dev_attr_occ_dvfs_power.dev_attr.attr,
+	&sensor_dev_attr_occ_mem_throttle.dev_attr.attr,
+	&sensor_dev_attr_occ_quick_pwr_drop.dev_attr.attr,
+	&sensor_dev_attr_occ_state.dev_attr.attr,
+	&sensor_dev_attr_occs_present.dev_attr.attr,
+	&sensor_dev_attr_occ_error.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group occ_sysfs = {
+	.attrs = occ_attributes,
+};
+
+void occ_sysfs_poll_done(struct occ *occ)
+{
+	const char *name;
+	struct occ_poll_response_header *header =
+		(struct occ_poll_response_header *)occ->resp.data;
+
+	/*
+	 * On the first poll response, we haven't yet created the sysfs
+	 * attributes, so don't make any notify calls.
+	 */
+	if (!occ->hwmon)
+		goto done;
+
+	if ((header->status & OCC_STAT_MASTER) !=
+	    (occ->prev_stat & OCC_STAT_MASTER)) {
+		name = sensor_dev_attr_occ_master.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->status & OCC_STAT_ACTIVE) !=
+	    (occ->prev_stat & OCC_STAT_ACTIVE)) {
+		name = sensor_dev_attr_occ_active.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->ext_status & OCC_EXT_STAT_DVFS_OT) !=
+	    (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_OT)) {
+		name = sensor_dev_attr_occ_dvfs_overtemp.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->ext_status & OCC_EXT_STAT_DVFS_POWER) !=
+	    (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_POWER)) {
+		name = sensor_dev_attr_occ_dvfs_power.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->ext_status & OCC_EXT_STAT_MEM_THROTTLE) !=
+	    (occ->prev_ext_stat & OCC_EXT_STAT_MEM_THROTTLE)) {
+		name = sensor_dev_attr_occ_mem_throttle.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->ext_status & OCC_EXT_STAT_QUICK_DROP) !=
+	    (occ->prev_ext_stat & OCC_EXT_STAT_QUICK_DROP)) {
+		name = sensor_dev_attr_occ_quick_pwr_drop.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if ((header->status & OCC_STAT_MASTER) &&
+	    header->occs_present != occ->prev_occs_present) {
+		name = sensor_dev_attr_occs_present.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	if (occ->error && occ->error != occ->prev_error) {
+		name = sensor_dev_attr_occ_error.dev_attr.attr.name;
+		sysfs_notify(&occ->bus_dev->kobj, NULL, name);
+	}
+
+	/* no notifications for OCC state; doesn't indicate error condition */
+
+done:
+	occ->prev_error = occ->error;
+	occ->prev_stat = header->status;
+	occ->prev_ext_stat = header->ext_status;
+	occ->prev_occs_present = header->occs_present;
+}
+
+int occ_setup_sysfs(struct occ *occ)
+{
+	return sysfs_create_group(&occ->bus_dev->kobj, &occ_sysfs);
+}
+
+void occ_shutdown(struct occ *occ)
+{
+	sysfs_remove_group(&occ->bus_dev->kobj, &occ_sysfs);
+}